fifis iffis ffiis ffiis iffis fifis fiifs ififs fiifs ififs iiffs iiffs ffiis ffiis fifis iffis fifis iffis ififs fiifs iiffs iiffs fiifs ififs fifsi iffsi ffisi ffisi iffsi fifsi fisfi ifsfi fsifi sfifi isffi siffi ffsii ffsii fsfii sffii fsfii sffii ifsfi fisfi isffi siffi fsifi sfifi fiisf ifisf fiisf ifisf iifsf iifsf fisif ifsif fsiif sfiif isfif sifif fisif ifsif fsiif sfiif isfif sifif iisff iisff isiff siiff isiff siiff ffisi ffisi fifsi iffsi fifsi iffsi ffsii ffsii fsfii sffii fsfii sffii fisfi ifsfi fsifi sfifi isffi siffi fisfi ifsfi fsifi sfifi isffi siffi ifisf fiisf iifsf iifsf fiisf ifisf ifsif fisif isfif sifif fsiif sfiif iisff iisff isiff siiff isiff siiff fisif ifsif fsiif sfiif isfif sifif
Note: these 'words' (valid or invalid) are all the permutations of the word fifis. These words are obtained by scrambling the letters in fifis.